Jet mixing of process fluids in fixed bed reactor

ABSTRACT

A fixed bed catalytic reactor for converting process fluids having an upper catalyst bed and a lower catalyst bed below the upper catalyst bed for converting process fluids flowing through the upper and lower beds. A mixing zone is located between the upper bed and lower beds, and at least one jet is provided for injecting an inclined fluid jet into the mixing zone against the flow of the process fluids to entrain process fluids within the jet and to radially mix the process fluids across the mixing zone.

FIELD

[0001] The present invention relates to mixing of process fluids in a fixed bed reactor. More particularly, the present invention relates to a method and means for injecting jet force to provide radial mixing of process fluids between catalyst beds in a fixed bed reactor.

BACKGROUND

[0002] Fixed bed reactors are often used in petroleum refining and chemicals for hydrocracking, hydroprocessing and reforming. These reactors are usually, but not necessarily cylindrical, and can have a diameter up to about 20 feet or larger, frequently with a height of about 20 ft to more than 100 ft, depending upon the application. Fixed bed reactors are filled with the catalyst particles, which are typically about 1 to 2 mm in size, but may be smaller or larger.

[0003] Typically, a reactor has multiple catalyst beds, two or more beds depending upon the application of the reactor. The usual feed to the reactor is an oil and may also include hydrogen. The purpose of the hydrogen depends on the operational function of the reactor, such as to hydrodesulfurize the feed, or to remove nitrogen, or to saturate aromatics, or to hydrocrack the feed.

[0004] In hydrocracking, processes having high temperatures and/or pressures and/or added hydrogen are used to crack large molecules into smaller more usable molecules. These reactors are used very often in petroleum industry for desulfurization, denitrogenation, aromatic saturation and hydrocracking.

[0005] There are many other reactions. But a common problem with the reactions in the fixed bed units is that most of the reactions are exothermic, i.e., as the feed flows through the reactor the temperature of the processed fluid increases. Further, these processes are constrained by radial temperature maldistributions. These temperature maldistributions cause significant safety and operations problems. For example, the safe operating windows in hydrocrackers is often constrained by temperature maldistribution in catalyst beds. In addition to safety, temperature maldistribution causes premature catalyst deactivation leading to much shorter run lengths. Also, temperature maldistribution often leads to poor product selectivity and higher hydrogen consumption.

[0006] Radial temperature maldistributions, i.e., temperature variations along the diameter of a catalyst bed may be quite significant, and at times the variations are as large as the temperature rise along the length of the bed. This lateral temperature maldistribution may be caused by many sources. There may be nonuniform flow, meaning higher vertical flow in one area of the bed than in other areas of the bed. When a fluid spends more time in the bed, the temperature can rise to a higher level, thus causing temperature gradients along cross-sectional portions of the unit. Such nonuniform flow can be caused by localized fouling, e.g., by an obstruction resulting from formation of polymer or coke in the catalyst bed. Nonuniform flow can also be caused by catalyst packing, which is not uniform and thus causes obstructions to occur more quickly in the more densely packed areas. There are many other reasons that may not be fully understood for causing radial temperature maldistribution. But, there is no doubt that there can be very large radial temperature maldistribution.

[0007] Temperature maldistribution in a catalyst bed normally gets propagated to the next downstream catalyst bed because of poor radial mixing in fixed beds. This propagated maldistribution gets further amplified because the reaction rates (heat generation rates) increase with temperature. This “snow balling” effect can lead to unsafe temperatures which can result in the above noted safety and operations problems, runaway reaction, catalyst deactivation, and catalyst fusion agglomeration.

[0008] Quench boxes, such as disclosed in U.S. Pat. No. 4,960,571, are often located between catalyst beds to control the reaction temperature and to provide radial mixing so that the temperature maldistributions from an upstream bed do not get propagated to a downstream bed. However, the quench boxes are expensive. Also, quench boxes are difficult to retrofit in existing reactors. U.S. Pat. No. 4,960,571 is hereby incorporated herein by reference.

[0009] It is apparent that there is a need for a simplified and relatively inexpensive technology to minimize temperature maldistribution in fixed bed catalytic reactors.

SUMMARY

[0010] In accordance with a broad aspect of the present invention, there is provided a fixed bed catalytic reactor for converting process fluids comprising an upper catalyst bed and a lower catalyst bed below the upper catalyst bed for converting process fluids flowing through the beds. A mixing zone is located between the beds, and means are provided for injecting at least one fluid jet into the mixing zone and inclined against the flow of the process fluids between the beds to entrain process fluids therein and to radially mix the process fluids across the mixing zone.

[0011] In accordance with another broad aspect of the present invention, there is provided a method of converting process fluids in a fixed bed catalytic reactor that includes an upper catalyst bed, a lower catalyst bed below the upper catalyst bed, and a mixing zone between the upper bed and the lower bed. The method comprises the steps of flowing process fluids through the beds and the mixing zone to convert the process fluids; and injecting at least one fluid jet into the mixing zone and inclined against the flow of the process fluids to entrain process fluids in the jet and to radially mix the process fluids across the mixing zone.

[0012] In a downflow reactor, the fluid jet is positioned in the lower portion of the mixing zone and is upwardly inclined against the flow of the process fluids; and in an upflow reactor, the fluid jet is positioned at the top of the mixing zone and is downwardly inclined against the flow of the process fluids.

[0013] In accordance with a specific aspect of the present invention, a downflow fixed bed catalytic reactor is cylindrically shaped, and a nozzle is installed in the mixing zone near the intersection of the bottom surface and the sidewall of the mixing zone. The nozzle is upwardly inclined to point at the top surface of the mixing zone and diametrically across the top surface from two-thirds to one diameter distance of the mixing zone. In this position, the nozzle injects an upwardly directed fluid jet against the flow of the process fluids from the upper bed to entrain process fluids therein and to radially mix the process fluids across the mixing zone prior to the process fluids flowing into the lower bed.

[0014] Jets mix by the entrainment of the surrounding fluid into the jet. The induced flow within the mixing zone is therefore greater than the jet flow itself and leads to rapid mixing. The amount of fluid entrained by a jet is a function of jet Reynolds Number, jet expansion angle and jet length.

[0015] Thus, in accordance with the present invention, radial temperature homogeneity is achieved between catalyst beds by using jet mixing. As will be described hereinafter, the source of the jet fluid can be external to the reactor and/or a portion of process fluids that is bypassed across an upper bed at high velocity. One or more jets can be used. In addition, baffle plates and jet nozzles may be used to maximize mixing. Also, the source of jet fluid can be an injected quench fluid. Accordingly, the instant invention provides a simplified and relatively inexpensive means and method for providing radial mixing between catalyst beds by using jet mixing to minimize temperature maldistribution in fixed bed catalytic reactors.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 is a side elevation view of a fixed bed reactor with portions in section showing a zone between upper and lower catalyst beds having a single nozzle in the zone for radially mixing process fluids in accordance with an embodiment of the present invention;

[0017]FIG. 2 is a schematic view of the mixing zone of FIG. 1 showing entrainment of process fluids by the fluid jet formed by the single nozzle;

[0018]FIG. 3 is a graphical representation of the preferred maximum nozzle elevation angle for radially mixing process fluids in the embodiment of FIG. 1;

[0019]FIG. 4 a graphical representation of the preferred minimum nozzle elevation angle for radially mixing process fluids in the embodiment of FIG. 1;

[0020]FIG. 5 is a schematic view of another embodiment of the present invention wherein a plurality of inwardly and upwardly directed nozzles are provided for radially mixing process fluids in a zone between catalyst beds wherein the nozzle is at the lower end of a conduit passing through the upper catalyst bed;

[0021]FIG. 6 is a cross-sectional view taken along line 6-6 of FIG. 5;

[0022]FIG. 7 is a schematic view of another embodiment of the present invention wherein the nozzle is at the lower end of a conduit passing through the upper catalyst bed;

[0023]FIG. 8 is a schematic view of yet another embodiment of the present invention for radially mixing process fluids in a zone between catalyst beds wherein the nozzle is at the lower end of a conduit passing through the upper catalyst bed; and

[0024]FIG. 9 is a side elevation view of another embodiment of the instant invention wherein a fixed bed reactor is shown with portions in section, and a zone between upper and lower catalyst beds having a single downwardly directed nozzle in the zone for radially mixing process fluids.

DESCRIPTION OF SPECIFIC EMBODIMENTS

[0025] With reference to FIGS. 1 and 2, there is shown a cylindrical fixed bed catalytic reactor 10 for converting process fluids. The reactor 10 has an upper catalyst bed 12 and a lower catalyst bed 14 below the upper catalyst bed 12 for converting process fluids entering the reactor 10 through an inlet conduit 11, flowing downwardly through the upper bed 12, a mixing zone 16, the lower bed 14, and exiting the reactor by an outlet conduit 26. The mixing zone 16 has a perforated top plate or surface 18 and a perforated bottom plate or surface 20 for passage of process fluids therethrough. Alternatively, the top surface of the lower bed 14 can function as the bottom surface of the mixing zone 16. Means including a nozzle 22 are provided in the mixing zone 16 for injecting at least one upwardly inclined fluid jet 24 into the mixing zone 16 against the flow of the process fluids (represented by the downwardly directed arrows) from the upper bed 12 to radially mix the process fluids prior to the process fluids flowing through the bottom surface 20 to the lower bed 14.

[0026] The mixing zone 16 extends transversely of the reactor 10 with essentially the same cross-sectional area as the upper and lower beds 12,14 to form a single non-compartmented chamber with no obstruction between the nozzle 22 and the top surface 18 or interior wall surface of the reactor 10 for baffling the fluid jet 24.

[0027] A distributor zone 30 preferably is positioned between the mixing zone 16 and the lower bed 14. It is common in fixed bed reactors to employ multiple catalyst beds with injection of gas or liquid between each pair of beds. Interbed injection may be needed to replenish depleted reactants, to quench the process fluids following exothermic reactions, or to introduce a different feed stream. If the beds contain different catalysts, it is possible to stage somewhat different reactions within a single vessel. In all cases, it is critical to establish good fluid distribution at the top of each catalyst bed. Suitable distributor systems are well known, such as those disclosed in U.S. Pat. Nos. 4,960,571, 5,484,578 and 5,799,877, which patents are hereby incorporated herein by reference.

[0028] The nozzle 22 is installed in the mixing zone 16 near the intersection of the bottom surface 20 and the sidewall 23 of the reactor 10. The nozzle 22 is preferably installed in the sidewall 23 for ease of access and maintenance. However, the nozzle may be positioned on the bottom surface 20 of the mixing zone 16.

[0029] The discharge velocity of the fluid jet 24 produced by the nozzle 22, and the exit opening of nozzle 22 have values adequate for providing penetration of the fluid jet across the interior of the mixing zone 16 and toward the top surface 18 on the far side of the mixing zone 16. The fluid jet is turbulent, and has a Reynolds Number>3000. Further, the exit opening of the nozzle 22 preferably is defined by: ${d \geq \frac{H}{400\quad {\sin (\theta)}}};$

[0030] wherein: d=nozzle exit diameter, feet;

[0031] H=distance of nozzle below the top surface of the mixing zone, feet; and

[0032] θ=nozzle angle of inclination above horizontal, degrees.

[0033] With particular reference to FIGS. 3 and 4, the nozzle 22 preferably is upwardly inclined to point diametrically across the mixing zone 16 at the top surface 18 from two-thirds (0.66T) to one diameter distance (T) of the mixing zone 16. The nozzle injects the fluid jet 24 against the downward flow of the process fluids from the upper bed 12 to entrain the process fluids in the fluid jet 24 as indicated by the curved arrows in FIGS. 2-4. The process fluids are thereby radially mixed across the mixing zone 16 prior to the process fluids flowing into the lower bed 14.

[0034] With reference to FIGS. 3 and 4, the nozzle 22 has an angle in degrees of inclination above horizontal of from θ° (FIG. 4) to θ′° (FIG. 3),

[0035] wherein: ${\theta = {\arctan \quad \frac{H}{T}}},$

[0036] ,degrees; ${\theta^{\prime} = {\arctan \quad \frac{H}{0.66T}}},$

[0037] ,degrees;

[0038] H=distance of nozzle below the top surface of the mixing zone, feet; and

[0039] T=mixing zone diameter, feet.

[0040] Preferably, the nozzle 22 has an angle of inclination above horizontal of from θ° as shown in FIG. 4 to (θ+10°), wherein: ${\theta = {\arctan \quad \frac{H}{T}}};$

[0041] wherein: θ=nozzle angle of inclination above horizontal, degrees;

[0042] H=distance of nozzle below the top surface of the mixing zone, feet; and

[0043] T=mixing zone diameter, feet.

[0044] More preferably, the nozzle 22 has an angle of inclination above horizontal of θ° as shown in FIG. 4.

[0045] In one embodiment of the present invention, the jet fluid is an injected quench fluid from an external source 19 (FIG. 1). As should be readily appreciated, the present invention is suitable for use in various catalytic processes through which reactants or partially reacted reactants and quench fluids are to be homogeneously mixed so as to control the temperature profile of such materials or their composition, or both. Indeed, the quench fluids may be all gases, all liquids or a mixture of gases and liquids, depending upon the nature of the process being carried out in the reactor. Quench fluids frequently contain hydrogen.

[0046] Thus, the present invention provides a quench stream in which the jet velocity and direction mixes all of the flow to provide a blended total flow having a more uniform radial temperature before the process fluid flow enters the next bed 14. As discussed above, the discharge velocity of the fluid jet 24, and the exit opening of the nozzle 22 need to have values adequate for providing penetration of the fluid jet across the interior of the mixing zone 16 and toward the top surface 18 on the far side of the mixing zone 16, and to provide a turbulent fluid jet having a Reynolds Number>3000. The velocity of the quench stream exiting the nozzle is very high, e.g., 300 ft/sec, which provides energy to direct the turbulent fluid jet against the flow of the process fluids from the upper bed 12 and thereby entrain a portion of the process fluids in the fluid jet 24 and radially mix the process fluids across the mixing zone prior to the process fluids flowing into the lower bed 14.

[0047] Jet mixing of the process fluids in accordance with the present invention provides an injection quench stream having a jet velocity sufficiently high to mix all of the process fluids in the mixing zone 16. Thus, the present invention provides for injecting the quench fluid to not only blend with one part of the process fluid flow but to blend with the whole total process fluid flow to make the process fluid flow more uniform from a temperature point of view before it enters the next bed 14.

[0048] With reference to FIGS. 5 and 6, the injecting means comprises a plurality of inwardly directed and upwardly inclined nozzles 40-43 to provide a plurality of opposing fluid jets 44-47 for entraining the process fluids therein as indicated by the curved arrows. In this embodiment, the nozzles 40-43 are equally spaced about the interior of the mixing zone 16.

[0049] With reference to FIG. 7, there is shown an embodiment wherein a conduit 70 passes downwardly through the upper catalyst bed 12 to bypass it. The conduit 70 has a nozzle portion 71 and an outwardly flared end 72 downstream of the nozzle portion 71. A deflecting platform 73 is spaced from the flared end 72 for deflecting the fluid jet exiting the flared end outwardly and upwardly as indicated by the curved arrows. The fluid jet exiting the flared end 72 radially flows outwardly and upwardly for 360° from between the flared end 72 and the deflecting platform 73.

[0050]FIG. 8 shows another embodiment wherein a conduit 80 passes through the upper catalyst bed 12 to bypass it. The conduit 80 has a nozzle portion 81 at the bottom end thereof. A deflecting means in the form an upwardly pointed conical structure 83 below the nozzle portion 81 is provided for deflecting the fluid jet exiting the nozzle portion 81 outwardly and upwardly as indicated by the curved arrows.

[0051] The embodiments of FIGS. 7 and 8 can provide for an automatic bypass if the top of a bed becomes very fouled as a result of an accumulation of non-process fluid substances, e.g., dust particles, sludge etc. Within a few months of starting a reactor with a fresh catalyst load the pressure drop across the bed builds up because of the accumulation of such non-process fluid substances. This build up may require that the reactor be shut down to permit reentry into the reactor for cleaning and perhaps restocking the catalyst in the reactor. To postpone reentry, the embodiments of FIGS. 7 and 8 can be used in shallow beds initially. When the bed is clean most of the flow will go to the bed and very little flow will go to the bypass tube. But, as the bed fouls the pressure drop across the bed and the tube increases resulting in a larger fraction of the process fluid flow entering the tube to bypass the bed.

[0052] As shown in FIG. 2, the source of the fluid jet can be through an upper bed bypass conduit 29 that passes through the upper bed 12 and/or a bypass conduit 28 that exits the reactor upstream of the upper bed 12 and/or a supply external to the reactor 27.

[0053] The high energy in such bypassing tubes has not been used in the prior art to a maximum efficiency. However, the embodiments of FIGS. 7 and 8 use this heretofore wasted energy to blend the process fluids in the mixing zone 16 before the process fluids enter the next bed.

[0054] The reactor of the present invention can be used in any fixed bed process such as a hydroprocessor for converting process fluids in one or more processes of hydrogenation, hydrodesulfurization, hydrodenitrogenation, hydrotreating, hydrofinishing and hydrocracking. The reactor can also be used to convert process fluids in an aromatic saturation process, or to convert process fluids in a reforming process with or without hydrogen.

[0055] The invention also contemplates an upflow reactor such as shown in FIG. 9 where the reactants enter at or near the bottom 126 of the reactor 1 10, flow upwardly through the lower bed 114 and the upper bed 112 as indicated by the arrows, and the reaction products are removed at or near the top 111 of the reactor 110. In this embodiment the means including a nozzle 122 are provided at the top or upper portion of the mixing zone 116 for injecting at least one downwardly inclined fluid jet 124 into the mixing zone 116 against the upward flow of the process fluids from the lower bed 114 to radially mix the process fluids prior to the process fluids flowing through the top surface 118 of the mixing zone 116 into the upper bed 112.

EXAMPLE

[0056] Following are calculations that were made as one example of the single jet embodiment of FIG. 2.

[0057] reactor diameter=12 ft;

[0058] mixing zone height=3 ft;

[0059] bed superficial velocity=0.5 ft/s;

[0060] density of the jet fluid (ρ)=2 lb/ft³;

[0061] V_(flow)/V_(jet)>10;

[0062] reactor flow rate (V_(flow))=56.5 ft³/s;

[0063] jet flow rate (V_(jet))=3 ft³/s;

[0064] jet nozzle sized at 1.8 in;

[0065] pressure drop at the jet nozzle (ΔP)=6.9 psi; and

[0066] time for one turn over=6 s.

[0067] The velocity of the jet stream 24 exiting the nozzle is at least 35 ft/sec, and may be in the order of 170 ft/sec. Preferably the nozzle discharge velocity is in the range of 35 ft/sec to 325 ft/sec to provide sufficient energy to direct a turbulent fluid jet against the flow of the process fluids from the upper bed 12 and thereby entrain a portion of the process fluids in the fluid jet 24 and radially mix the process fluids across the mixing zone 16 prior to the process fluids flowing into the lower bed 14.

[0068] Although the present invention has been described with reference to specific embodiments, it is to be understood that modifications and variations may be utilized without departing from the spirit and scope of this invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be part of the invention, provided they come within the scope of the appended claims and their equivalents. 

What is claimed is:
 1. A fixed bed catalytic reactor for converting process fluids comprising: an upper catalyst bed and a lower catalyst bed below said upper catalyst bed for converting process fluids flowing through said upper bed and said lower bed; a mixing zone between said upper bed and said lower bed, said mixing zone having a top surface and a bottom surface; and means for injecting at least one fluid jet in said mixing zone, said fluid jet being directional inclined against the flow of said process fluids between said upper bed and said lower bed to radially mix said process fluids.
 2. The reactor of claims wherein said process fluids flow upwardly from said lower bed, through said mixing zone and through said upper bed, and wherein said fluid jet is downwardly inclined against the flow of said process fluids.
 3. The reactor of claim 1 wherein said process fluids flow downwardly from said upper bed, through said mixing zone and through said lower bed, and wherein said fluid jet is upwardly inclined against the flow of said process fluids.
 4. The reactor of claim 3 further comprising a distributor zone between said mixing zone and said lower bed.
 5. The reactor of claim 3 wherein said injecting means comprises a single upwardly inclined nozzle to provide one fluid jet for entraining said process fluids therein.
 6. The reactor of claim 3 wherein said injecting means comprises a plurality of inwardly directed and upwardly inclined nozzles to provide a plurality of opposing fluid jets for entraining said process fluids therein.
 7. The reactor of claim 6 wherein said plurality of nozzles is equally spaced about the interior periphery of said mixing zone.
 8. The reactor of claim 6 wherein said fluid jets contain quench fluids supplied from a source exterior of said reactor.
 9. The reactor of claim 8 wherein said quench fluids contain hydrogen.
 10. The reactor of claim 5 wherein said fluid jet contains quench fluids supplied from a source outside of said reactor.
 11. The reactor of claim 10 wherein said quench fluids contain hydrogen.
 12. The reactor of claim 6 wherein said fluid jets contain a portion of said process fluids that bypasses said upper bed.
 13. The reactor of claim 5 wherein said fluid jet contains a portion of said process fluids that bypasses said upper bed.
 14. The reactor of claim 13 wherein said injecting means comprises means for conducting the bypass process fluids through said upper bed to said single nozzle to provide said one fluid jet.
 15. The reactor of claim 12 wherein said injecting means comprises means for conducting the bypass process fluids through said upper bed to said plurality of nozzles to provide said plurality of fluid jets.
 16. The reactor of claim 5 wherein said injecting means comprises a conduit extending from above said upper bed, downwardly along the outside of said reactor and into said mixing zone to bypass a portion of said process fluids around said upper bed, said conduit having said nozzle at an end thereof to provide said fluid jet.
 17. The reactor of claim 6 wherein said injecting means comprises a plurality of conduits extending from above said upper bed, downwardly along the outside of said reactor and into said mixing zone to bypass a portion of said process fluids around said upper bed, each one of said conduits having one of said plurality of nozzles at an end thereof to provide said opposing fluid jets.
 18. The reactor of claim 2 wherein said mixing zone extends transversely of said reactor and has essentially the same cross-sectional area as said upper bed and said lower bed.
 19. The reactor of claim 2 wherein said mixing zone is a single non-compartmented chamber.
 20. The reactor of claim 2 wherein said mixing zone has no obstruction between said injecting means and said top surface or interior wall surface of said reactor for baffling said at least one fluid jet.
 21. The reactor of claim 3 wherein said mixing zone extends transversely of said reactor and has essentially the same cross-sectional area as said upper bed and said lower bed.
 22. The reactor of claim 3 wherein said mixing zone is a single non-compartmented chamber.
 23. The reactor of claim 3 wherein said mixing zone has no obstruction between said injecting means and said top surface or interior wall surface of said reactor for baffling said at least one fluid jet.
 24. The reactor of claim 5 wherein said nozzle has an exit opening and said fluid jet has a discharge velocity, said exit opening and said discharge velocity having values for providing penetration of said fluid jet across the interior of said mixing zone.
 25. The reactor of claim 24 wherein said discharge velocity is at least 35 ft/sec.
 26. The reactor of claim 24 wherein said discharge velocity is in the range of 35 ft/sec to 325 ft/sec.
 27. The reactor of claim 5 wherein said nozzle is installed near the intersection of said bottom surface and a sidewall of said mixing zone.
 28. The reactor of claim 5 wherein said reactor has a cylindrical shape, and wherein said nozzle is installed in a low part of a side wall of said mixing zone and is upwardly inclined to point diametrically across said mixing zone at said top surface from two-thirds to one diameter distance of said mixing zone.
 29. The reactor of claim 5 wherein said reactor has a cylindrical shape, and wherein said nozzle is installed on said bottom surface of said mixing zone near said side wall and is upwardly inclined to point diametrically across said mixing zone at said top surface from two-thirds to one diameter distance of said top mixing zone.
 30. The reactor of claim 24 wherein said fluid jet is turbulent.
 31. The reactor of claim 24 wherein said fluid jet has a Reynolds Number>3000.
 32. The reactor of claim 24 wherein said reactor has a cylindrical shape, and wherein said nozzle has an angle of inclination of θ° to (θ°+10°) as defined by: ${\theta = {\arctan \quad \frac{H}{T}}};$

wherein: θ=nozzle angle of inclination above horizontal, degrees; H=distance of nozzle below said top surface of said mixing zone, feet; and T=mixing zone diameter, feet.
 33. The reactor of claim 32 wherein said nozzle has an angle of inclination of θ.
 34. The reactor of claim 24 wherein said reactor has a cylindrical shape, and wherein said nozzle has an angle in degrees of inclination above horizontal of between θ° and θ′°, wherein: $\theta = {\arctan \quad \frac{H}{T}}$

${\theta^{\prime} = {\arctan \quad \frac{H}{0.66T}}};$

H=distance of nozzle below said top surface of said mixing zone, feet; and T=mixing zone diameter, feet.
 35. The reactor of claim 24 wherein said reactor has a cylindrical shape, and wherein said exit opening is defined by: ${d \geq \frac{H}{400\quad {\sin (\theta)}}};$

wherein: d=nozzle exit diameter, feet; H=distance of nozzle below said top surface of said mixing zone, feet; and θ=nozzle angle of inclination above horizontal, degrees.
 36. The reactor of claim 14 wherein said injecting means comprises means in said mixing zone for deflecting said one fluid jet outwardly and upwardly to entrain said process fluids in said one fluid jet.
 37. The reactor of claim 15 wherein said injecting means comprises means for deflecting said plurality of fluid jets inwardly and upwardly to entrain said process fluids in said fluid jets.
 38. The reactor of claim 36 wherein a conduit having said single nozzle is outwardly flared at an end thereof downstream of said single nozzle, and wherein said deflecting means is spaced a predetermined distance from said conduit end for deflecting said one fluid jet outwardly and upwardly.
 39. The reactor of claim 38 wherein said one fluid jet flows outwardly and upwardly for 360° from between said conduit end and said deflecting means.
 40. The reactor of claim 36 wherein said deflecting means comprises an upwardly pointed conical structure below said nozzle to direct said one fluid jet outwardly and upwardly within said mixing zone.
 41. A cylindrically shaped fixed bed catalytic reactor for converting process fluids comprising: an upper catalyst bed and a lower catalyst bed below said upper catalyst bed for converting process fluids flowing downwardly through said upper bed and said lower bed; a mixing zone between said upper bed and said lower bed, said mixing zone having a top surface, a bottom surface and a side wall; and a nozzle installed in said mixing zone near the intersection of said bottom surface and said side wall, and upwardly inclined to point diametrically across said mixing zone at said top surface from two-thirds to one diameter distance of said mixing zone, said nozzle providing an upwardly directed turbulent fluid jet against the flow of said process fluids from said upper bed to entrain said process fluids therein and radially mix said process fluids prior to flowing into said lower bed.
 42. The reactor of claim 41 wherein said nozzle is installed in said sidewall.
 43. The reactor of claim 41 wherein said mixing zone extends transversely of said reactor and has essentially the same cross-sectional area as said upper bed and said lower bed.
 44. The reactor of claim 41 wherein said mixing zone is a single non-compartmented chamber.
 45. The reactor of claim 41 wherein said mixing zone has no obstruction between said nozzle and said top surface or said side wall for baffling said fluid jet.
 46. The reactor of claim 41 further comprising a distributor zone between said mixing zone and said lower bed.
 47. The reactor of claim 41 wherein said fluid jet contains a quench fluid provided from the exterior of said reactor.
 48. The reactor of claim 47 wherein said quench fluid contains hydrogen.
 49. The reactor of claim 41 wherein said fluid jet contains process fluids that bypass said upper bed.
 50. The reactor of claim 41 wherein said nozzle has an exit opening and said fluid jet has a discharge velocity, said exit opening and said discharge velocity having values for providing penetration of said fluid jet across the interior of said mixing zone.
 51. The reactor of claim 50 wherein said discharge velocity is at least 35 ft/sec.
 52. The reactor of claim 50 wherein said discharge velocity is in the range of 35 ft/sec to 325 ft/sec.
 53. The reactor of claim 41 wherein said fluid jet has a Reynolds Number>3000.
 54. The reactor of claim 41 wherein said nozzle has an angle of inclination of θ° to θ+10° as defined by: ${\theta = {\arctan \quad \frac{H}{T}}};$

wherein: θ=nozzle angle of inclination above horizontal, degrees; H=distance of nozzle below said top surface of said mixing zone, feet; and T=mixing zone diameter, feet.
 55. The reactor of claim 54 wherein said nozzle has an angle of inclination of θ.
 56. The reactor of claim 41 wherein said nozzle has an angle in degrees of inclination above horizontal of between θ° and θ′°, wherein: ${\theta = {\arctan \quad \frac{H}{T}}};$

${\theta^{\prime} = {\arctan \frac{H}{0.66T}}};$

H=distance of nozzle below said top surface of said mixing zone, feet; and T=mixing zone diameter, feet.
 57. The reactor of claim 50 wherein said exit opening is defined by: ${d \geq \frac{H}{400\quad {\sin (\theta)}}};$

wherein: d=nozzle exit diameter, feet; H=distance of nozzle below said top surface of said mixing zone, feet; and θ=nozzle angle of inclination above horizontal, degrees.
 58. The reactor of claim 41 wherein the reactor is a hydroprocessor and includes means for converting process fluids in one or more processes of hydrogenation, hydrodesulfurization, hydrodenitrogenation, hydrotreating, hydrofinishing and hydrocracking.
 59. The reactor of claim 41 wherein the reactor includes means for converting process fluids in an aromatic saturation process.
 60. The reactor of claim 41 wherein the reactor includes means for converting process fluids in a reforming process with or without hydrogen.
 61. A method of converting process fluids in a fixed bed catalytic reactor comprising an upper catalyst bed and a lower catalyst bed below said upper catalyst bed and a mixing zone between said upper bed and said lower bed, said mixing zone having a top surface and a bottom surface; said method comprising the steps of: flowing process fluids through said upper and lower beds and said mixing zone for converting the process fluids; and injecting at least one fluid jet into said mixing zone and inclined against the flow of said process fluids from said upper bed to radially mix said process fluids across said mixing zone prior to said process fluids flowing to said lower bed.
 62. The method of claim 61 wherein said process fluids flow downwardly from said upper bed, through said mixing zone and through said lower bed, and said fluid jet is upwardly inclined in said mixing zone against the downward flow of said process fluids; and wherein said nozzle has an exit opening and said fluid jet has a discharge velocity, said exit opening and said discharge velocity having values for providing penetration of said fluid jet across the interior of said mixing zone.
 63. The method of claim 62 wherein said fluid jet is turbulent.
 64. The method of claim 62 wherein said fluid jet has a Reynolds Number>3000.
 65. The method of claim 63 wherein said reactor has a cylindrical shape, and wherein said nozzle has an angle in degrees of inclination above horizontal of between θ° and θ′°, wherein: ${\theta = {\arctan \frac{H}{T}}};$

${\theta^{\prime} = {\arctan \frac{H}{0.66T}}};$

H=distance of nozzle below said top surface of said mixing zone, feet; and T=mixing zone diameter, feet.
 66. The method of claim 63 wherein said reactor has a cylindrical shape, and wherein said exit opening is defined by: ${d \geq \frac{H}{400\quad {\sin (\theta)}}};$

wherein: d=nozzle exit diameter, feet; H=distance of nozzle below said top surface of said mixing zone, feet; and θ=nozzle angle of inclination above horizontal, degrees.
 67. A method of converting process fluids in a cylindrically shaped fixed bed catalytic reactor comprising an upper catalyst bed, a lower catalyst bed below said upper catalyst bed and a mixing zone between said upper bed and said lower bed, said mixing zone having a top surface, a bottom surface and a side wall; said method comprising the steps of: flowing process fluids downwardly through said upper bed, said mixing zone and said lower bed for converting the process fluids; a mixing zone between said upper bed and said lower bed, said mixing zone having a top surface, a bottom surface and a side wall; and installing a nozzle in said mixing zone near the intersection of said bottom surface and said side wall, and inclining said nozzle upwardly to point diametrically across said mixing zone at said top surface from two-thirds to one diameter distance of said mixing zone to provide an upwardly directed turbulent fluid jet against the flow of said process fluids from said upper bed to entrain said process fluids in said fluid jet and radially mix said process fluids across said mixing zone prior to said process fluids flowing into said lower bed.
 68. The method of claim 67 wherein said nozzle has an exit opening and said fluid jet has a discharge velocity, said exit opening and said discharge velocity having values for providing penetration of said fluid jet across the interior of said mixing zone.
 69. The reactor of claim 68 wherein said discharge velocity is at least 35 ft/sec.
 70. The reactor of claim 68 wherein said discharge velocity is in the range of 35 ft/sec to 325 ft/sec.
 71. The method of claim 68 wherein said fluid jet has a Reynolds Number>3000.
 72. The method of claim 68 wherein said nozzle has an angle in degrees of inclination above horizontal of between θ° and θ′°, wherein: ${\theta = {\arctan \frac{H}{T}}};$

; ${\theta^{\prime} = {\arctan \frac{H}{0.66T}}};$

; H=distance of nozzle below said top surface of said mixing zone, feet; and T=mixing zone diameter, feet.
 73. The method of claim 68 wherein said exit opening is defined by: ${d \geq \frac{H}{400\quad {\sin (\theta)}}};$

; wherein: d=nozzle exit diameter, feet; H=distance of nozzle below said top surface of said mixing zone, feet; and θ=nozzle angle of inclination above horizontal, degrees. 